Following the events right after "JX6-a: A New Beginning" Dark Vegan returns to destroy the Earth with an upgraded armada. Dark Vegan, with his upgrade armada, is cutting up the Earth's trees, taking off the oxygen and sucking up the Earth's water. Johnny, Dukey, and the Johnny Stopping Evil Force 5 team up to stop Dark Vegan and return the Earth's resources.
Johnny drinks an unstable isotope so he can get sick and not have to study for a test for school. Unfortunately, not only does the isotope give him red spots and a purple tongue, if it's not cured within four hours, it's going to give him immense bloating, cause violent coughing, and eventually make him explode.
Johnny is upset because the holidays that give free candy to the world are spread too far apart, so Johnny decides to start his own holiday, known as Kids Get Free Candy Day, and try to spread free candy. When there are some adult protests against this holiday, Johnny, Dukey, Susan, and Mary gain an unlikely ally against this – the Beekeeper.
Mr. Black and Mr. White ask Susan and Mary to design a new weapon, so they make a helmet that allows the user to control things with their mind. But it becomes a huge mistake when it's stuck on Johnny's head, and his obsession with a new video game now makes any inanimate object he sees turn into a monster.